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Post by thelegacy on Mar 26, 2019 18:40:40 GMT
Just called my FCC agent friend 3/26 at 2:12 PM and He Answered. Very nice agent I tell you. I asked him about part 15:236 and the ONN brand Wireless headphones sold at Walmart and Walmart.com and the frequency of 84.95 Mhz. Told him in the Walmart review someone went on a boat in the lake and picked up the signal 1/4 to a mile away. and a friend of mine went in his car and threw his Radio into japan FM mode and although slightly off frequency he heard it.
He told me to try and find the Wireless Headphone and send a picture and any information I could about it. What he said is that Walmart sold Wireless cameras and other devices that the FCC had to pull off the shelf because though they were certified they were way past spec and there was a problem with these devices causing interference to other services. He says anything FM related will not go 1/4 to 1 mile legally even though its not in the broadcast band due to interference issues these devices are causing.
Furthermore there has been a on slot of faulty certified FM transmitters that has been tested in a private lab that when he tested it as an electronics engineer for the FCC found they were not suitable for part 15 and again he has tried to get these devices off the shelf due to interference issues and some of the owners of these devices had to be asked to turn these devices off.
He said he'll have to check into some of the newer rules for part 15:236 and get back with me on this. So I'd say until I can get the devices in question sent to him for verification we should not use them. We don't need to have any issues with this.
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Post by mark on Mar 26, 2019 21:36:09 GMT
Very good idea! To check with your agents.
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Post by Boomer on Apr 3, 2019 2:42:54 GMT
I've tried different FM mics over the years, those used to be a popular and cheap way to have a wireless mic, and most electronics stores had them. I don't think they were 50 milliwatts, just under the regular rules for FM broadcast band and could do a few hundred feet range. It still was good enough for a kid to play being a DJ. Electronics magazines had articles to build 2 or 3 transistor FM mics, building it into a case with a mic element, 1960s-'70s. The articles would specify a 3-4 inch antenna, but if you knew what you were doing and put an actual resonant dipole antenna at the RF output and tapped the output coil right, it would give the signal more kick, enough for broadcasting to a local area. That was a secret among tech kids of the day, and not valid now because of drift. Really, all of the old FM mics aren't any good to try now due to drift, and just getting any distance with them would be hard, it's when the bands were clearer and noise lower, and you had a good receiver to attach to a PA. Right, Legacy, baby monitors used to use AM radio, names like Radio Nurse and such. It's been a while since I read about them, but I think they were made to broadcast to the AM radio you already had, and maybe were carrier current and broadcast the signal through electrical lines to your own AM radio in the area. I had the notion they used a loop type antenna coil, but carrier current seems to be a more reasonable idea to reach a whole house or to outside at a neighbor's. One thing I know that used carrier current above the AM band were 1970s cordless phones, the base unit. I used to hear them a good bit, there was always someone in conversation around 1.7 mhz, and from the talk, I swore that someone I heard was 2 miles away. That's with a longwire antenna on a navy receiver, but it shows what's possible. Boomer
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w9lwa
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Post by w9lwa on Apr 9, 2019 19:24:57 GMT
Well, I think this is a good idea and it should work, at least on 87.9 since it looks like most fm receivers will pick that up. The technical requirements and restrictions should be easy enough to deal with, the 15.236 definition of a wireless microphone is pretty non-restrictive and I don't see any restrictions on programing. The 15.236 definition doesn't seem to require it, but if I do this, I think I'll probably get an actual wireless microphone transmitter unit, just to avoid arguing the point if it comes to that. I see several on the internet and a couple on ebay that are stereo, whatever that means in ebay wireless mic lingo. I think I'll probably put something together to record off the air everything I transmit since the 15.236 wireless mic definition lists one of the permissible uses as transmitting to a recording device. From my experience of learning everything the hard way, more compliance is usually better than less compliance.
All comments and suggestions welcome and encouraged. I usually need all the help I can get...
John W9LWA
I suppose I should add that I'm new here so hello to everyone and thanks for letting me in.
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Post by mark on Apr 9, 2019 23:56:58 GMT
I've checked this out just for my own info and look closely at the ones you see on Ebay and Amazon. Most are not transmitting on 87.7 or 87.9, they are in the UHF and above the aviation band somewhere around 160mhz and higher. The ones the bands use on stage for guitars and mics are not in the frequencies you want. Even the ones in VHF. There's certain frequency ranges these can legally go and most except for much older ones, if you can find them, are not at 87.7 and 87.9.
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w9lwa
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Post by w9lwa on Apr 10, 2019 1:58:11 GMT
Yes, I certainly agree the availability of the wireless mics in question isn't that great. Most I've seen are indeed in other frequency bands. But, the 15.236 definition of wireless mics is pretty loose:
Wireless Microphone. An intentional radiator that converts sound into electrical audio signals that are transmitted using radio signals to a receiver which converts the radio signals back into audio signals that are sent through a sound recording or amplifying system.
This doesn't seem to include anything that requires the transmitting unit to have been marketed as a wireless mic or otherwise resemble what we might think a wireless mic is or looks like. Even so, if any of those few I've seen that operate on the subject frequency band are actually any good, I'd still tend to want to use one because I think the FCC would have a tough time saying I'm not using a wireless mic when the apparatus was commercially built for such purpose. Could be wrong in the eyes of FCC Enforcement, but I think it's a solidly defensible position were the matter to wind up in front of a Judge...
I appreciate your observations.
John W9LWA
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Rich
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RF Systems Engr (retired)
Posts: 112
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Post by Rich on Apr 10, 2019 10:41:03 GMT
... I think the FCC would have a tough time saying I'm not using a wireless mic when the apparatus was commercially built for such purpose. ... Might the FCC issue here be that even though an apparatus was designed for use as a wireless mic, the deliberate use of it for reception by anyone with a suitable receiver means that in fact, it is not being used solely as a wireless mic?
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w9lwa
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Post by w9lwa on Apr 10, 2019 16:07:00 GMT
... I think the FCC would have a tough time saying I'm not using a wireless mic when the apparatus was commercially built for such purpose. ... Might the FCC issue here be that even though an apparatus was designed for use as a wireless mic, the deliberate use of it for reception by anyone with a suitable receiver means that in fact, it is not being used solely as a wireless mic?
I suppose someone at the FCC could take that position but it looks to me like they'd be attempting to enforce regulatory language that doesn't exist. As far as I can see, there isn't anything that limits the usage of wireless mics or the intended audience. If a client came in with this issue, I'd probably make a list of things s/he could do to make things as much as possible like traditional wireless mic use but would not restrict the signal for pickup by anyone within range listening on 87.9. Now admittedly, its been a long time since I've dealt directly anyone in FCC Enforcement. But, there is an FCC Enforcement Committee at the Federal Communications Bar Association. I'm a member of the FCBA but have never been particularly active. I'm thinking I might seek appointment to that committee and perhaps I'll get some insight as to what they're thinking over at the FCC these days. If I get anything useful, I'll try and pass it along... Thanks for your comments. John W9LWA
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Post by thelegacy on Apr 14, 2019 6:59:44 GMT
This should be very interesting because I did ask the FCC agent that once visited my house because of issues with my FM transmitter. What he said was there's nothing stopping me from giving out the frequency of a wireless headphone and telling people to listen to me on that frequency since the device is certified.
That being said the old 49 megahertz baby monitors could easily be used as a hobby radio station and one could simply tell people to TuneIn on 49.860 for example. Now there is no language that says that a baby has to be coming out of the audio of those monitors.
The only reason I really brought it up is that some people prefer the quality of FM as opposed to 8 am. But with C-Quam AM stereo you do have a better chance I've actually getting listeners.
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w9lwa
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Post by w9lwa on Apr 14, 2019 19:07:04 GMT
That wouldn't be greatly different from transmitting on 87.9 with a wireless mic, except since most FM radios will tune down that far, the potential audience could be a lot bigger. I think I'm just going to transmit on AM with a Rangemaster. But, since I'm installing it some distance from the house, the plan is to get a good quality wireless mic to feed the Rangemaster from a studio in the house. 87.9 here is dead quiet so I'll transmit on that from the house to the AM transmitter. I suppose someone could intercept the 87.9 between the house and the Rangemaster, but I imagine I can live with that.
I do like to record everything I transmit, so the 87.9 signal will also feed the recorder which indeed is allowed under 15.236.
It all looks legal to me...
John W9LWA
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Post by thelegacy on Apr 15, 2019 3:05:12 GMT
50 mW can pack a wallop and could go 1/4-1 mile on a Car Radio!! When I was sort of being stupid and running 7 Watts on FM I never had an issue for 2 yrs 24/7 on 87.7 Mhz in Stereo. I had a ground plane at the time and as soon as we had that TV station come on the air on 12/23/17 I went off air. I switched to 100.1 and in two days I got the knock. At the time I figured if it was on Amazon and everyone was buying one of these it could not be all that bad so long as I chose a blank frequency and there was one blank above and below the one I choose. How wrong I was because within two days on February 20, 2018 at 2:42 PM during a Live show I received the knock at the door from uncle Charlie.
Keep in mind too there are plenty of really powerful Bluetooth AV senders/receivers that do go quite far. There is also 900 Mhz whereas if you put the sender in a box and have the antenna line of sight from the receiver you may just be able to do that too and not risk any visit from the FCC.
Being your a licensed Ham they will be a lot more strict if you break the rules and it could cost you your hard earned Ham ticket and that would be a shame as I'm now studying for the license and I have most of the Rules down but that math may kill me when test time comes when I decide to pursuit this goal.
Good Luck and stay safe from Uncle Charlie.
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w9lwa
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Post by w9lwa on Apr 16, 2019 0:36:39 GMT
Thanks for the information, Legacy. I'll be careful to follow the rules. I think it will be interesting to see how it all works out. I suppose I should start thinking about what kind of studio equipment to get and what kind of programing I should broadcast.
Should be fun...
John W9LWA
Good luck with that ham license. If I can do it, you can do it.
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Post by thelegacy on Apr 16, 2019 15:24:58 GMT
UPDATE: I found the FCC ID to the ONN Wireless Headphone on 84.922 Mhz and E-Mailed my FCC Agent I have met personally!!Now I told him about 15:236 and the fact this question was brought up and even gave him this forum to look at the questions. This guy is really nice and I think it would be cool to have a Real FCC agent answering some of these questions. So far from what I saw on this item here is what data I have: Wireless Headphones ONN FM Wireless Headphones ONA14AA011 FCC ID 2ABV4-ONA14AA011 FCC Website to search the ID: www.fcc.gov/oet/ea/fccidWhen I type the Grantee code which was 2ABV4 and press search without the product code I found it in the list of other wireless devices this company sells and got approval for. This unit was the Only one on 84.922 Mhz this is why I double checked with the agent and even told him what us hobby broadcasters want to do. at 5mW this thing will travel to a car Radio at a sensitivity of 0.9 microvolts. Like I said a friend has one and when he threw his car Radio to the Japanese FM mode it went over a mile with his transmitter near a window. Even with the headphone itself he heard it far well over what you hear for part 15 section 239 legal unlicensed FM transmitting. And again no place do we see we can't give out the frequency to all our friends and tell them to throw their Radios into Japanese FM mode if there is a hack for that Radio or where to buy a Radio that will go down there. Plus there are older analog TV sound Radios you can easily tune to 84.922 Mhz which could be a national Hobby Broadcast Frequency as we can all buy these headphones on Ebay and WE HAVE LIFT OFF Huston!! We'll all agree to only use that frequency not FM transmitters from 88.1-107.9 Mhz. The Headphones are $20-35 rather you buy New or Refurbished. Some Walmart stores sold them too. Say your prayers now so we get the OK from the FCC I'm all so excited about this.
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w9lwa
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Post by w9lwa on Apr 16, 2019 16:44:24 GMT
What does that mean to put the radio into Japanese FM mode? Is this some alternate band on radios in Japanese cars? Sounds interesting.
John W9LWA
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Post by thelegacy on Apr 16, 2019 19:58:07 GMT
What I've found is that some car Radio's imported into the USA from Japanese manufacturers like Mitsubishi, Sony have a secret two button combination where when held down at the same time will throw the Radio into international mode and then you can tune down to 76 Mhz. Now remember the headphones I described transmit on 84.922 Mhz. Its slightly off frequency but just like the channel 6 Franken FM stations which the audio is actually 87.75 Mhz and the AFC on some Radios will cover this I do believe it should do the same for the .922 at the end. Unless I find a device certified and ends in .1, .3, .5 you know. But at least we have something that may work for a way to get what we really want and that is FM Album Rock quality sound.
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